Monolithic integration of compound semiconductor (Group III-V or II-VI) devices and silicon (Si) devices on a common Si substrate has the potential for achieving very substantial improvements in the performance of Very Large Scale Integrated (VLSI) circuits. In particular, monolithic integration of a gallium arsenide (GaAs) compound semiconductor device and silicon (Si) devices on a common substrate enhances capabilities of the VLSI circuit by combining the performance of silicon circuits with gallium arsenide and/or aluminum gallium arsenide optoelectronic components and high speed gallium arsenide and/or aluminum gallium arsenide circuits.
For example, the through-put of a silicon VLSI system may be considerably increased by integrating high-speed gallium arsenide input and/or output circuits, signal processing units and/or cache memory devices. As another example, gallium arsenide/aluminum gallium arsenide optoelectronic interface units may provide high-data-rate optical links to replace wire interconnects between silicon VLSI subsystems.
While there exists a 4% lattice mismatch between gallium arsenide and silicon, device-quality gallium arsenide layers have been grown on silicon substrates by both molecular beam epitaxy (MBE) and organometallic chemical vapor deposition (OMCVD). For true monolithic integration, however, it is necessary to fabricate both gallium arsenide and silicon devices on the same wafer or substrate. To achieve this goal, a method for selectively depositing III-V materials on silicon substrates would be highly desirable.